Drive unit with a hydrodynamic retarder and transmission

Abstract

A drive unit for a motor vehicle having an engine; a transmission featuring a transmission housing; and a retarder featuring a rotor and a stator. A retarder shaft is provided that is supported by two bearings which are offset along the axial length of the retarder shaft. At least one of the bearings ("outside bearing") is supported by a wall ("outside wall") of the transmission housing. The retarder shaft protrudes freely beyond the outside wall of the transmission housing. Disposed on the retarder shaft, outside the outer bearing, on the outside wall, is a sealing component. The sealing component seals the clearance between the retarder (or pinion) shaft and the outside wall, preventing passage therethrough of the transmission oil and the operating medium of the retarder.

What is claimed is: 
     
       1. A drive unit for a motor vehicle having an engine, said drive unit comprising: a transmission, said transmission a transmission housing defining an outside wall of said transmission, said housing containing transmission lubricant therein;   a retarder in the form of an independent module having an operating medium and a cooperatively disposed rotor and stator disposed therein, said retarder module being separate from said transmission housing outside wall; a retarder shaft extending through an aperture in said transmission outside wall and protruding freely beyond said outside wall and extending into said retarder module, said shaft having said rotor mounted thereon;   two bearings rotatably supporting said shaft; and     a sealing component disposed between said shaft and said outside wall sealing a clearance between said shaft and said outside wall against said transmission lubricant and said operating medium, said transmission lubricant being separated from said operating medium.   
     
     
       2. The drive unit of claim 1 wherein said retarder shaft is a hollow shaft. 
     
     
       3. The drive unit of claim 1 wherein said outside wall comprises a cover joined to a remaining portion of said transmission housing and said outside wall supports one of said retarder and said retarder shaft. 
     
     
       4. The drive unit of claim 3 wherein said retarder shaft is a hollow shaft. 
     
     
       5. The drive unit of claim 3 further comprising a gearing arrangement, said gearing arrangement including a pinion disposed on said retarder shaft. 
     
     
       6. The drive unit of claim 5 wherein said pinion is disposed on said retarder shaft between said two bearings. 
     
     
       7. The drive unit of claim 1 further comprising a gearing arrangement, said gearing arrangement including a pinion disposed on said retarder shaft. 
     
     
       8. The drive unit of claim 7 wherein said pinion is disposed on said retarder shaft between said two bearings. 
     
     
       9. The drive unit of claim 7 wherein said retarder shaft is a hollow shaft.